No Windows Boot Manager in BIOS Boot Sequence

I have a Dell Inspiron 15 7000 (7567) laptop. I have Windows 10 installed and I tried to dual boot Ubuntu on my SSD. On Ubuntu partition section, i realized there is no Windows Boot Manager visible for me to pick for ubuntu boot loader. 

After that i went to my BIOS menu and Windows Boot Manager was not in the UEFI Boot Sequence list. I tried to Add Boot Option manually like this https://www.youtube.com/watch?v=tloprA25JE8,

but it gave me the error "File system not found". 

Windows is running without any errors, but i don't understand why the boot manager is not listed. What should i do?

Thanks